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Glycemic Load Testing or, the case for Sourdough

August 7, 2009 - 7:21pm

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Glycemic Load Testing or, the case for Sourdough

I have done some amount of research on the subject of how Sourdough breads affect persons with Diabetes. As a person afflicted by this disease, I take it seriously and while I'm not a very good follower of my Dr's orders, I do make efforts in certain areas to control my sugar levels. My own experience was that my blood sugar went and stayed down when I ate breads risen with a natural yeast. That isn't to say the same will happen to you but I wouldn't bet against it.

I was directed to a set of scientific papers done in Europe by some prominent scientists at a University concerning this subject. The short story is that they made 8 loaves of bread. 2 each of 4 types. In each type the bread was risen by commercial or natural (sd) yeast. Otherwise the breads were identical. The testing was done to determine the glycemic load of each bread on a healthy person. The results are remarkable. It shouldn't be a surprise that our bodies digest natural products more easily than commercial pretenders.

I won't even pretend to understand it all, but I too have noted that my blood sugar tends not to spike after eating sourdough bread, even though it's white sd bread. If I have a piece last thing at night, my blood sugar is not high in the morning, and it will stay level as long as I stick to sd bread.

I agree on the effect, but calling applying instant dry yeast a "commercial pretender" is nonsense. IDY is simply another natural creature that grows at enhanced rates in factories (yeast farms?) and is dried and made into granules for easy application. It is still a "live" organism.

While I do not know of any conclusive data, the following excerpt shows that at the very least the acid content has an effect. Thus it is not natural vs. "unnatural" yeast (which is wrong anyway, see above), but rather the side effect of using the natural leavens which causes a "sour" bread, with the "sour" doing its business.

The application of the sourdough technique (preferments) is found strongly in the world of artisan breads, and almost not at all in many factory breads. Add all the "nasty" additives in factory bread, and you have another good reason why sourdough bread is lower in GC load.

Another known factor is that a higher amount of fiber or bran in a bread, lowers its glycemic load. Many artisan breads tend to incorporate at least some portion of whole wheat, bran, germ etc, as opposed to just white flour. Also, artisan breads are less designed to be as soft and fluffy as "those other ones". Flour used is often a little coarser. The resulting higher fiber content and/or different food particle sizes also positively affect glycemic load. So, if you really want to benefit, go for sourdough with whole wheat in it!

enhanced anything loads us up with chemicals that alone may not be harmful, but in combination with others we eat can sometimes produce an unhealthy body. A plant fed chemical fertilizer grows as well as one fed organic fertilizer. The plant only knows its fertilizer, but we are more healthy for eating the naturaly fed one. Such as the case with chickens fed hormones to speed up growth. Good for the economy of the chicken farmers, but look what it has done to consumers.

My father is also diabetic and can eat natural sugars with little or no effect on his blood sugar level. But processed sugar sends it through the roof. Sugar is sugar so you say. Processing and enhancements have no effect on the body? We each have to do what is best for our own bodies. Your opinion of whole grain being better is very true. And by making our own breads, we are in control of the things we put into it. If natural yeast is better for some, wonderful. If one is allergic to gluten, it can be fixed by controling ingredients, and the list goes on. I think every baker on here is already a step ahead, just by making his or her own bread. Don't get me wrong, I'm not arguing with you about the nature/chemical issue. Not into the Peace, Love, and everything is a Consipracy bit, not from that era. Just reinforcing that each person is different. Sort of like agreeing with you but in a totally unusual way. Your breads are top notch. And your family is lucky you are such as gifted baker, that you care what goes into their body and for their wellbeing.

" enhanced anything loads us up with chemicals that alone may not be harmful, but in combination with others we eat can sometimes produce an unhealthy body."

But that makes no sense in this context. The only difference between commercially leavened versus naturally leavened bread is 1) the yeast variety, and 2) the presence or absence of additional bacteria. That's it. I mean, it's not like commercial yeast contain "chemicals" or "toxins", as you'd like to put it.

In that context, commercially leavened breads are actually more "pure", in the sense that they're innoculated with *just* yeast, and nothing more.

" If natural yeast is better for some, wonderful."

But that's the whole point. It's not. Natural yeast, commercial yeast, it's all yeast. The difference is in all the *other* bacteria that are present and working in sourdough.

In short, there's nothing at all wrong with commercial yeast. They aren't "pretenders". They're just yeast. The only difference is that, in commercially leavened bread, they're forced to work by themselves, and so you don't get those other nutritional benefits that the lactobacilli and other critters contribute to the mix.

What I said is the IDY is not fairly called "a commercial pretender". "Sugar is sugar so you say. Processing and enhancements have no effect on the body?". Where on earth did I say that? Where did I give an opinion on whole wheat? I repeated and referred to prior research ((I don't disagree with that, and I encourage you to eat ww, but it wasn't my opinion, it is research) in an response to the original poster and hoping it was informational. You are somehow or other climbing on the bandwagon of your cause (which I support) and turn this into something it shouldn't be. This post, and my reply, was about why sourdough might be better from a glycemic load perspective. I am trying to educate. You, sort of, apologize later in your message, but you start of completely wrong.

Regarding yeast: Is it commercial? Yes, you buy it from a merchant after all. So is the flour (or berries) you use, your salt etc. Is it a pretender? Hardly. Yeast is an organism only different in strain and behavior from the yeasty beasties and bacteria found in natural levain.

Yeast (Saccharomyces cerevisiae): This is the crucial ingredient, and by its vary nature, is purely organic, not chemical

sorbitan monostearate: sometimes referred to as "synthetic wax", an approved food additive. Although I don't know, I suspect here it is being used to keep clumps of yeasties together in granules. Chemical: yes. Amount: not specified. More on wikipedia

ascorbic acid: Don't know perse why they add this, but certainly helps your bread's dough qualities. Known and often used additive to bread, even in the artisan world. Also known as vitamin C and generally considered safe and beneficial. Chemical? I guess you could call anything in this world a chemical. This is a naturally occurring substance in many foods

Consider that in most breads the IDY does not consitute more than 2% of the flour weight, which at 60% hydration often means less than 1.25% of total bread mass. Also consider that the IDY consists of 98+% yeasties and the non-yeasty stuff (which I don't consider a problem anyway, but you do) will be less than 2% of the 1.25%, or 0.025%, or 2.5ppm. That is very little of an arguably not very relevant subtance (asc. acid, and sorb. stereate).

Now consider your naturally leavened bread. Unless you buy your wheat berries straight from the field, know that the wheat wasn't sprayed or treated, mill your own flour, know that your mill is clean, buy your salt certified pure NaCl (I do not think one can buy this, and even if you can, the cost will be prohbitive. You dn't use iodized salt, do you?), and also have your water cleaned, distilled and radiated so that it is 100% pure H2O (cost prohibitive), you are probably right that its is "cleaner" (your perspective) than otherwise the same bread based on IDY.

I would also suggest that it probably would not taste very good. The influence of minerals etc. in water has been shown to have relevant effect on taste of bread, dough qualities etc. I am going to venture a guess, because I don't have all the quantitive information, that most of us who make bread with natural levain are still using "contaminated" (what a term) ingredients and the difference between IDY vs. natural is probably much less relevant than other "crap" introduced via other ingredients (bleached flour, iodized salt, dough conditioners, etc.). The choice for sourdough from a diabetic's perspective should be based primarily on its proven glycemic load benefits first and foremost. That's where a diabetic's primary focus would lie. Removing other pollutants can be next, but is likely of equal concern in IDY based or sourdough breads.

All I am trying to say with all that is that it is always laudable to strive to eat food products, whether bought or self-made, that are as clean of "polutants" as reasonably possible. One can, however, easily go overboard in doing some kind of incomplete thinking and analysis of what actually happens in the overall product. I would like to state here that my discussion above is likely also incomplete, but I bet a whole lot more founded that yours.

If you think I don't understand that everybody is different, you should go read the latest threads on the forum of the Bread Bakers Guild of America (of which I am a member, and to read it you would have to be one too, which I would encourage any somewhat serious home baker to do, it is not expensive and a great resource) where I just used my "expertise in that area" (haha) to try and calm down a large number of people very upset with each other, just because they do not understand that very issue: all people are different.

Don't get your blood pressure up over what I said. I was having a bad day, miss read what you wrote, and later as you say "sort of appologized". Hmmm. I am greatful to Eric for the article, as I said,my father is Diabetic and can benefit from the information. You defininately put me in my place though, Yes I am a home baker and proud of it. A great percentage of the people who post on here are just that, home bakers. I shouldn't have gotten in the conversation in the first place, as we little women need to keep our place and be seen and not heard. You don't have to impress us with your fancy club, we care about what you bake. All are welcome here. Even the humble home baker. Sorry I don't come up to your standards. I appologize AGAIN for my comments.

Your title and first sentence says it all. You let your mouth (fingers) run way ahead of your head and it appears you are still having a bad day. If so, I am sorry for you.

Again you make inferences that are invalid. Just because I am a BBGA member does not mean I am a professional. In fact I am not, I encouraged home bakers to join, and so does this "fancy club" (several TFL members are also members), and had you checked me out a little, you would know that.

You imply something that is completely unfounded, and you put yourself down in a way that is completely unnecessary (the reference to "little women and where they belong") and useless. My standards hardly matter, but I do expect respectful behavior and accurate statements, and I think most of us would.

An apology made after this uncontrolled outburst comes across as insincere. However, I don't need your apology. I usually try once to make people see they're mistaken, no more. There are plenty people here and elsewhere that know me, and know that all this is completely untrue and unfounded, and that actually value my contribution. So I suggest, for the sake of TFL, that we just end this thread here.

And I never dreamed I'd be able to eat white bread again without fear! I do like oatmeal bread, and often make non-sourdough bread using instant yeast, and with lots of good things like oat bran or Red River cereal or coarsely ground whole wheat. When I was first diagnosed 8 years ago, I was told that's it for white bread, but now I'm able to convert my favourite white bread to sourdough and it's delicious. I have nothing against yeast in whatever form, dried or homemade, but if I make a commercial yeast bread, it will have to be whole wheat.

Many store bought bread products, in particular white ones, have lots of added sugar. That alone is the single biggest reason against eating white bread. Most people have only store bought as an option. Furthermore, the cheapest breads often have the largest amounts of additives and other unwanted stuff. (If you can't afford a more expensive bread, you'll appreciate a bread that doesn't go stale for 2 weeks!)

If you make your own and just use flour, water, yeast and salt, you are already doing way better than the store stuff (store sold good artisan breads excepted). Yes, if you can go sourdough as well, you are doing even better, but beware: some sourdoughs have other additives that negate what your trying to do. The use of honey, or other sweeteners is sometimes seen, as well as additives such as raisin (raisin walnut bread). These can be just as "killer" from a glycemic load perspective. So just the sourdough label is not the whole story. Know the ingredients!

The point of the thread is to note a scientific basis to expect a lower glycemic load form any sourdough bread compared to any like commercial yeast product. Obviously adding sugar or other high carbohydrate items to either bread will increase the load.

I think the paper noted above, did a good job of documenting the advantage of baking with a natural levain, regardless of the kind of bread. Can we not accept this evidence and find some pleasure in the findings?

Thanks Eric for posting that piece of information, it was music to my ears. I was diagnosed a few years ago with Glocose Intolerance and was told to foget simple carbs if I wish to avoid diabetes and should be very careful even with complex carbs.

I'm in day 7 at the moment of cultivating my pineapple sourdough starter and hope to be using it soon. This post is wonderful news, I'll check my sugar levels with both breads and see if I find a difference.

Good luck with the new starter. I think you will find working with your own starter to be liberating. Once you begin to understand that you can change it in terms of how the feeding will effect the flavor of the breads, well the sky's the limit. Knowing that everything you bake is just a little bit better for you is motivation to me personally.

I'm very happy to report that my Starter is alive and is finally in action. Today is day 8, I fed it as I have been doing in the last few days, 1/4 cup each white all purpose flour and bottled water but it still didn't look all that active. I've learnt here that I could add a 1/2 tsp of apple cider vinegar to adjust Ph level and help it take off. I added a few drops of rice vinegar (what I had on hand) and 1Tsp whole what flour and it finally doubled in about a couple of hours.

I'm looking forward to baking with my new baby more now that I know it's better for my family.

I started SD baking of my daily bread about 10 months ago. I eat a fruited WW bread for breakfast and have a sandwich with SD WW almost daily. I have just added homemade yogurt to my accomplishments. What a difference it has all made! My fasting blood sugar is noticeably lower and I feel generally healthier. When we have gone on vacation away from home the reversion is noticeable,even though I follow the same eating pattern using commercial products. (I'm not a big restaruant eater-we usually make our own meals on vacation with an occasional lunch or dinner out.) I don't test blood sugar so I can't attest to a daily effect. I do know that when I get back on my "regime" I feel so much better.

There are some gaps in this paper that I would be interested in. First, are they comparing yeast varieties or fermentation times or the influence of the lactobacillus on the yeast? The commercial yeast they use is s cerevisiae, which is the natural yeast used since earliest recorded times for baking, and is usually cwlled baker's yeast. It's what you get dried or (as I do) fresh. Sourdough, to quote Wikipedia, is "The yeasts Candida milleri or Saccharomyces exiguus usually populate sourdough cultures symbiotically with Lactobacillus sanfranciscensis."

Different yeast varioeties, but that may be regional. The real differences in sourdough are twofold: the inclusion of the lactobacillus, which gives it the distinctive taste and also retards the gluten formation and the slow fermentation process.

Here's where I climb on my own personal hobbyhorse. Most commercial bread is now made using the Chorleywood process. This is a forced rising method that practically eliminates the action of yeast on the flour. It reduces the rise from hours to minutes. While I've not found any studies on this (haven't really started looking, yet), to my mind it means that the flour is not worked on before you eat it. In a sourdough or slow fermentation bread, the kind most of us make, the yeast has a chance to digest and process the flour, creating gluten chains and processing the sugars and starches. If you have a gluten sensitivity, my money is on the effects of eating bread baked by the Chorleywod process messing up your digestive system. After all, if bread made so many people ill, it would hardly have lasted as a staple food for most of human history and even become sacred ("give us this day our daily bread" and so forth.)

Interesting thread. Maybe the benefit of the sourdough is not due to the yeast. Might it be that the wheat in sourdough is more "digested?" For instance, sprouted wheat flour is supposed to be easier to digest than regular flour. Similarly, or on the other hand, resistant starches increase glycemic load less than starches that are absorved right away. (That's why WW is better for diabetics -- and for everyone else too.) Point is, maybe it's the flour. The flour in the regular and in the sourdough breads might end up being different.

I wonder if they ever tested rye breads cooked with those loooong baking sessions we know. After all that bread comes out sweet for a reason: I guess it's full of maltose. It would be interesting having some data on this subject.

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